Solve for $x$ and $y$ using substitution. ${5x-3y = -10}$ ${y = -4x+9}$
Answer: Since $y$ has already been solved for, substitute $-4x+9$ for $y$ in the first equation. ${5x - 3}{(-4x+9)}{= -10}$ Simplify and solve for $x$ $5x+12x - 27 = -10$ $17x-27 = -10$ $17x-27{+27} = -10{+27}$ $17x = 17$ $\dfrac{17x}{{17}} = \dfrac{17}{{17}}$ ${x = 1}$ Now that you know ${x = 1}$ , plug it back into $\thinspace {y = -4x+9}\thinspace$ to find $y$ ${y = -4}{(1)}{ + 9}$ $y = -4 + 9$ $y = 5$ You can also plug ${x = 1}$ into $\thinspace {5x-3y = -10}\thinspace$ and get the same answer for $y$ : ${5}{(1)}{ - 3y = -10}$ ${y = 5}$